CA1194271A - Rapidly cast alloy strip having dissimilar portions - Google Patents

Abstract

Abstract of the Disclosure A rapidly quenched, cast metallic strip is disclosed comprising a plurality of dis?imilar portions, each portion metallurgically alloy-bonded during casting to adjacent portions along the longitudinal extent of the strip. In the method and apparatus for producing such strip stream of molten metal is delivered onto a casting surface from a first crucible and at least one additional dissimilar stream of molten metal is delivered onto the casting surface such that a peripheral edge of the dissimilar stream contacts a peripheral edge portion of adjacent dissimilar metal to create a metallurgical alloy-bond therebetween during casting.

Description

Brief Summary of the Inventlo~

The pre~ent 1nvention relates to a new and improved metalllc ~trip ~aterial; and more particularly to a rapidly cast ~etal ~trlp having dissimilar longitudinal portions metallurgically ~lloy-bonded to one another durin~ casting of the strip. This invention also pertàins to a me~hod and apparatus for producing such ~trip.

This invention is directed to strip ~aterials, whether amorphous, crystalline or combi na tions thereof, having dissimilar portlons. In a preferred embod1ment this invention relates to metal alloys in strip form, at least a portion of whlc~ are ~morphous. In this speclfication the term Wamorphous~ is intended to refer to composition in which at least 50~ is amorphous, which ls typlcally measured by X-ray defraction.

Since the early l900's it has been taught, such as ln U.S. Patents 905,758 and 993~904, that metallic strip material could be continuously produced by delivering molten metal to a moving chill surfaceO ~ore recent developments, ~uch as U.S~ Patent 49142,571 teach specific refinements in strip casting nozzle structure to aid in the production of strip material. Also, various references, including V.S.
Patent 3,856,513, disclose preferable alloys, particularly or the production of amorphous strip and wire material.

For certAin appl i~ations, it has been found beneficial to ~oin 3t least two sheets bf strip materi~l along thelr longltudinal axis. Such joining can be used to obta~n a strip having a greater overall width, or can be

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1 u~ed to ~oin di~simil~r portions. Common techniq~e~ for joining a pluality of strips include welding, brazlng and 601dering. ~owever~ certain ~actoræ, including the heat, and partlcularly the heat gradient, generated in ~elding, brazin~
and ~oldering can advex~ely affect the qualit.y of such compo~ition or the quality of the mul~iplex strip material.

As mentioned above, a preferred embodiment of the present invention pertains to ~trip material in which at least one dissimilar portion is amorphous. Amorphous metal alloys are tho~e produced ~y a process in which crystallization i6 avoided, typically by extremely rapidly quenching the metal from the liquid 6tate. Such cooling rate is usually on the order of at least about 104C per second. Because of their atomic arrangement and composition, some amorphous alloys can po~sess enhanced properties, including higher strength and increased resistance to chemical attack when compared to conventional crystalline alloys. ~herefore, such amorphous alloys may be ideally auited for uses includin~ but not limlted to razor blade edge material6 due to their properties of ~trength, hardness, ductility and corrosion re~istance. Certain amorphous material~ are al~o known to possess enhanced magnetic and electrical propert~e~ and the 6trip of the present invention may be des~rable for electrical ~nd use~.

The pre~ent invention applie~ egually to rapidly cast crystalline matexials whlch have a multitude of uses.
The present lnvention further comprehends corn~inatlons of dts~imllar cryst~ ne materials, dissimilar amorphous material6 and comb~nation6 thereof where lt is deslrable to ~3 2~

1 utlli~e ~uch dissi~ilar materials ~o decrease the overall cost of the composite, or mul~iplex strip, or to locali~e desired properties, gage, etc. of dissimilar materials in a composite ~trip. For example, the present invention may be utilized to produce delirate material by simultaneously providing edge portions of a more rugged material which would facilitate the handling of the delicate material. After production, the handling portions could easily be trimmed from the strip. Also, this invention could be utilized to join alloys w~ich exhibit different thermal elec~ric properties, suitable f~r use in the production of thermocouples or multiple theremocouples.
Additionally, the present invention may be employed to cast strip having varying gages acros~ the width thereof to lntentionally vary the mechanical strength, electrical properties, etc. across the width of the strip. Further, this invention can be used to produce ~trip having alloys of varlo~s expansion characteristics across the width thereof. ~hus, by heating such ~trlp an intentional curvilinear strip config~ration ~ may be obtained. It ~hould be underfitood that a variety of applications can be made of the strip of this invention, and that the above examples àre merely lllustratLve and ~hould not be interpreted ~s l~miting the scope of this invention in any manner.

Accordingly, a new and improved multiplex strip material i~ desired in which dissimllar portlons are joined in a ~hion whlch does not adver6ely affect either the overall quality of ~uch lndivldu~l str~p components or the integrity of each of ~uch strips. ~ikewise, a new and lmproved method and ~pparatu6 for producing such str~p component~ and multiple~ comblna~ions i~ desired.

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1 The present invention may be summarized as providing a new and lmproved r~pidly, quenched cast metallic strip comprising a plurallty of dlsslmilar portions, ~ach portlon metallurgically alloy-bonded during casting ~o adjacent portions ~long the longitudlnal extend of the etrlp~ In the method and apparatus for producing such 6trip a strea~ of molten metal ls delivered onto a casting surface from a first crucible and at least one additional disslmilar ~tream of molten ~etal is delivered onto ~he casting surface such tha~
a peripheral edge of the dissimilar stream contacts a peripheral edge port~on of adjacent dissimllar metal to create a metallurgical alloy-bond therebetween during casting.

Among the advantages of the present invention is the abillty to combine a plurality of dissimllar portions into a composite strip material wlth a metallurglcal alloy-bond between adjacent dlssimlar portions which is oreated during the casting of such 6trip material without adversely affectlng the quali~y or properties of the individual strip portions.

An objective of the present invention is to provide a strip of r~pidly cast materlal having at least two disslmilar portions ~e~allurgically alloy-bonded along the length of She strlp thereby forming a multiplex strip, or composite ~trip, exhlbiting dlfferent propertles, structure or quallty ln ~ach portion of the stripr Another advantage o the present invention is the provi~ion of a method and an apparatus or rapldly easting a ~trlp comprised of d~sslmllar portlons metallurgically ~5--~lloy-bonded to one another along the length of the strip during the castlng operatisns without adversely affecting the quallty or the properties of the strlp ~ater~

It follows that a further advant~ge of the present invention is that where strength, corrosion resistance and other qualities are required only at an edge or at the edges of the strip material, the expensive alloying ingredients, such as cobalt and molybdenum only have to be used at such edge portlons of a multiplex strip material, thus reducing the cost of the strip.

Another objective of this invention is to provide a ~trip of meta~lurgicslly alloy-bonded amorphous ~nd crystalllne portlons without causing ~he amorphous portion to crystallize during the bonding thereof. Another objective is to provide a strip of components joined at a transition zone wherein an alloy formed at the transition zone has enhanced properties over those of the joined portions.

These ~nd other objectives and advantages wlll be more fully understood and appreclated wi~h reference to the followlng detailed description and to the accompanying drawings.

Brief Descriptlon of the ~rawings -Fi~ure 1 18 a front cross-sect~onal view of an apparatus of the pr~sent invention.

25~igure 2 ls an enlarged cross-sectlonal view of the nozzle ~r~a of the ~pparatus shown in Figure 1 1 Figure 3 is a partial perspective view illustrating an alternatiYe apparatus of the present lnvention.

~Igure 4 is perspective view of ~he casting surface and the strip cast thereon fro~ the appar~tus shown in Figure 3D

Figure 5 is a top elevation vlew of an alternative apparatus of the present lnvention.

Figure 6 is a perspective view of an alternative apparatus of ~he present invention.

Figure 7 is a cross-sectional vlew o a preferred crucible and nozzle of the present lnvention.

Figure 8 is a graph of an energy dispersion X-ray analysis for the element nlckel taken acro~s the strip of the Example.

Figure 9 ls a graph of ~n energy dispersion X-ray ~nalysis for the element silicon ~aken across the strip of the Example.

Flgure 10 is a graph of the Knoop hardness at a load of 200 grams taken across the strip of the Exa~ple.

Detailed Description Referring partl~ularly to the drawings, Figures 1 and 2 illu~trate a preferred apparatus of the pr2sent ~nvention.
As shown in Figure 1 this apparatus lncludes a first crucible 10 having sn internal c~vity designed to receive ~nd hold molten ~etal. The first cruclble 10 alEo includes a nozzle 4~

1 lOa through whlch a first stream of molten metal ls delivered from the cavity to a casting ~urface 18. In a preferred embodiment the continuous strip material 30 is cast on a reltaively ~mooth, outer peripheral ~urface 18 of a circular drum or wheel 13~ If should be appreciated that ~onf~gurations other than clrcular may be employed, for example, the strip of the present invention could be cast onto a moving belt as shown in Figure 6, onto the lnterlor surface of a drum, between a pair of facing rollers, into a quench fluld, or the like, In a preferred ~mbodiment, the casting element 13 comprises a water cooled, precipitation hardened copper alloy wheel containing about 90% copper. Copper and copper alloys are chosen for their hlgh thermal conductlvity and wear resistance, however, steel, brass, aluminum, ~luminum alloys or other ~aterlals may be utilized alone, or multlpiece wheels having sleeves of molybdenum or other material may also be employed. Likewise, cooling may be accomplished with the use of a medium other than waterO Wa~er ls chosen for ~ts low cost and its ready avallabllityO

In the operation of the strip castlng apparatus of the present invention, the outer peripheral surface 18 of the casting wheel 13 must be able ~o absorb the heat generated by contact ~lth molten metal at the initial castlng point, and ~uch heat must dlffuse substantially lnto the copper wheel during each ro~ation Df ~he wheelO Removal of the diffused heat may be ~ccompllshed, for example, by delivering a ~ufflclent quAntlty ~ water through internal passageways 27~

located near the periphery of the c~Etlng wheel 13.
~lternatively, the cooling ~edium may be dellvered to the under6ide of the ca6ting surface. ~nder~tandably, rerigerDtion techni~ue~ and the like ~ay be employed to ~u~t ~nd optimize cooling rates, for example, to effec~uate wheel ~xpan~ion or contraction during strip ca6ting.

Whether a drum, wheel or ~elt iR employed for casting, the ca~ting surf~ce 18 ~hould generally be smooth and ~ymmetrlcal to maximize uniforml~y ~n str~p casting.
For example, in certain strip castlng operat~ons wherein it is desired to cast uniform gage strip, the distance be~ween the outer peripheral sasting ~urface 18 and the surfaces defining the oriFice or the nozzle 10~ or ~la which ls feeding the molten material onto the casting surface 18 ~hould not substantially dev~ate from a desired or set distance. This distance ~hall hereinafter be called ~tandoff distance or gap. It is under~tandable that the gap a~ each nozzle 6hould normally be substanti~lly ~aintained constant throughout the castlng operatlon when ~t: 16 the lntentlon of the operator to cast uniform, gage strip portions from that no~zle. If, however, controlled variations of thickness are desired either ln the complete composlte or ln certain component 6trips of the compo~lte, then programmed standoff distance both for the whole nozzle component ~rr~y ~nd/or for each contributing nozzle may be employed.

It ~hould al80 he understood that ~f ~he cast~ng element ls a drum or a wheel, the element Mhoula be carefully constructed 80 as not to be out-of-round durlng operation to in~ure uniformlty ln ~trip c~sting. Along 1 these lines, lt has been found that a drum or wheel which is out-of-round by about 0.020 inch, or more, may have a magnltude of di~ensional ~n~tability which, unless corrected or compensated during operation, may be unacceptable for certain strip casting operations. It has been found that acceptable dimensional symmetry may be accompli6hed by fabricating a wheel or drum from a single, integral ~lab of cold rolled or forged copper. However, as mentioned above alternative materials may be employed.

The molten materials to be cast in the apparatus described herein is preferably retained in a crucible or tundish, which ls provided with a corresponding no7zle.
The nozzle is typically, thou~h not necessarily, located at a lower portion of the crucible 85 shown in the drawings.
The nozzle may be an integral part of the crucible, or may constitute a separate material affixed into the crucible.

The crucible is constructed for receiving and holding molten metal therein. It will be appreciated ~ that appropriate materials must be utilized for the crucible to withstand the molten metal conditions, and where the crucible is not a monolithic ~tructure, the joints and ~eams between 6eparate pieces of the crucible must be assembled to prevent molten metal leakage during sustained operation.

One preferred crucible 10 for continuous production of rapidly cast ~trip material 1~ illustrated ln detail ln Figure 7. It should be understood that the molten metal holding portlon of the crucible 10, which is formed be~ween the lnside surface~, may take a variety of forms or ~hapes.

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Bowever, ~n a preferred embodiment an upper portlon of the crucible 10 has a significantly larger cross-sectional volume than that of the nozzle area of the cruc~ble 10 in order that the m~lten metal head height, ~bove the nozzle S lOa, is ~ubstantially unaffected by minor variations in molten metal volume in the cr~cible 10. Such ~tructure contr~butes to the maintenance of a subst3ntlally constant metallostatic head pres~ure at the nozzle, even with minor variations in metal volume that ~ay occur ln the crucible 10 in sustained or contlnuous casting operations. It should be ~ppreciated that casting may also be effected under externally applied pressure equipment which could be directly controlled.

As shown in Figure 7, it is also preferable that the inside surfaces of the crucible 10 conYerge toward one another in the direction of the nozzle lOa, and that such inside surfaces be radiused, rounded or generally curvilinear at locations of turns or bends in the cruclble 10 to ~ini~ize metal turbulence therein during a c~stirlg operation.

The molten metal holding area, formed between the lnside surfaces of the crucible 10 ~hown ln ~lgure 7 should be enclosed, such as with sidewalls. It is noted that the width of the crucible nozzles of the present lnvention ~hould not be limited~ It has been found that ~ crucible lO
and nozzle lOa of the present inventlon may be constructed by fir~t cuttlng or carvlng refr~ctory boardst such dS
lnsulating boards made from fiberized kaolin, lnto the desir2d ~h~pe, 6uch as ~h~t shown in Figure 70 Any number of these boards 42 may be ~t~cked upon one another to obtain the d~sired cruclble 10 ~nd nozzle lOa width. There is not 27~L

1 expected to be ~ rsstriction on the maximum wldth of the cruclble and nozzle of the present invention, and widths in excess of thlrty slx Inches for ~rip portions from onP
crucible are co~prehended by the present inventlon. After the requisite number of boards ~re stacked, the lnside surfaces may be sanded or otherwise finlshed ~o provlde generally smooth ~nslde sur~aces across the width of ~he stacked elements forming the cruclble 10. It should also be understood that single piece mater~als may be used to ~onstruct ~ monolithic crucible ln which case stacking would not be necessary. After the carved boards are stacked, the stack may be disposed between uncarved boards, which ~ay serve as the sidewalls for the crucible 10.

To hold the stacked boards, in~luding the sidewalls in positlon, ~t has been found convenien~ to dispose a metal plate against the outside surface of each sidewall and to bolt the plates together a~ a sultable number of locatlons about the crucible, thereby tlghtly compactlng the cruclble assembly. With such assembly, a mlnor amount of molten metal may tend to flow into the seams between the boards, but the compaction of the ~ssembly causes the metal to freeze, and ~hereby arrest the flow before lt sdversely affects the crucible or ~he strip casting operation. It should be understood tha~ the crucible of the present inventlon may be assembled with refractory cements, or the llke, or may be constructed of a monolothic s~ructure whlch does not require assembly.

As discussed ~bove, a nozzle 15 loca~ed ln each cruclble, preferably ln ~ lower portlon thereof. The 4~

1 nozzle comprises an orifice passa~e defined between inside surEaces oE the crucible. In a preEerred embodiment as illustrated in Figure 7, the nozzle lOa is formed between a crucible surface and an inside surface of an insert 50. A
portion of the inside surEace of the insert 50, is preferably disposed agains-t a portion of a ridge ~ormed by an outside surface of the crucible 10~ ~he structure of such preferred crucible is more ~ully described in copending Canadian Patent Application Serial No. 377,13~, entitled Apparatus for S-trip Casting, filed on May 8, 1981.
I-t should be appreciated that the insert 50, described in a preferred crucible of the presen-t invention, may be easily replaced, although it is preferred that the inserts 50 and the crucible be reused, either together or separately. It should also be noted that damage to an insert 50 shall not render the entire crucible unserviceable.
In the event of such insert damage, the insert 50 is merely replaced and the process may continue.
In a preferred embodiment, as shown in cross-section in Figure 7, the insert 50 is provided with a front edge surface 70. In such embodiment, the front edge surface 70 faces the casting surface 18 and is disposed to within less than 0.120 inch o~ the casting surface 18. Preferably, the front edge surEace 70 is disposed to wi-thin 0.080 inch and in a more preferred embodiment, to within 0.020 inch of the casting surface 18. It is also preferred that in such embodiment the front edge surface 70 be in substantially complete parallelism with the casting surface 18 movable therebelow.

f 1 insert 50, such complete paralleli6m may be accompli hed by placing ~ ~heet of sandpapert or the like, ~gain~t the casting ~urface 18 with the grit ide of the sandpaper facing the in6ert 50. By movlng the 1n~ert 50 lnto tight contact with the casting surface 18, w~th the ~andpaper disposed therebetween, ~nd by moving the castlng ~urface ~nd 6andpaper simultaneously past the ln~ert 50, the front edge ~urface 70 is ground by the grit ~ide of the sandpaper lnto 6ubstantially complete parallellsm with the casting ~urface 18. Such ~ubstantially complete paralleli~m may be achleved even when round or other curvillnear castlng ~urface are employed. To achieve such p~ralleli~m ~y this procedure 400 or 600 grit sandpaper has been found to be adequate. Other 6urfaces of the cruci~le ~ay be b~ought into ~ub6tantially complete paralleli~m therewith by this same procedure.

By maintaining the front edge eurface 70 in substantially complete parallelism with the castiny 6urface 18, the standoff distance9 or gap, betwleen th@ front edge surface 70 and the ca6ting surface 18 i3 maintained throughout the length thereof. It has been found that the gap between the front edge surface 70 and the casting 6urface 18 should be mai~ined at 1~88 than about 0.120 inch in order to 6uccessfully Cast trlp materlal. Preferably, this gap i8 maintained a~ les~ than ~bout 0.080 lnch ~nd for casting certain alloys lnto thln gage ~trip, gaps le~s than 0.020 inch are preferred. Alternatively~ ~he corner of the ~nsert 50 Lay Come to ~ polnt st the front edge 70 at a ~0 ~unction of the front edge of the lnsert 50, as opposed to a defined ~urface length as discussed ~bove.

1 Wh~t i~ pre~erred with respect to the bottom ~urface of ~he nozzle lOa is that such ~urface be disposed as close ~s possible to ~he castlng surface lB, without causing any lnterference for the moveable casting surace therebelow. Accordingly, the such 6urface of the nozzle ~ay just clear the casting surface 18, i.e., perhaps withln about .002 inch. Such spaclng must not be large enough to allow slgnificant molten metal backflow therebetween durlng castlng. It should be understood tha~ provisions may have to be made for edge portionC of strip material which may have to pass under a portion of another downstream crucibleD

The crw ibles 10 or 11 are preferably constructed of a material having superior insulatlng ability. If the insulating abillty 1~ not sufficient to retain the molten material at a relatively constant temperature, auxiliary heaters such as inductlon coils 12 may have to be provided in and/or around the crucibles 10 and/or 11, or resistance elements such as wires may be provided. A convenient material for the crucibles is an insulating board made from fiberized koalin, a naturally occurring, high purity, alum~na-silica fire clay. Such insulating material is available under the trademark Kaowool HS board. However, for sustained operations, and for casting higher mel~ing temperature nlloys, various other materials may have to be employed for constructing the crucible or the nozzle of the cruclble including silica, ~lumlna~ graphite, ~lumlna graphlte, clay graphite, ~re cl ay, quartz, boron nitrlde, ~llicon nitride, boron c~rblde, silicon carbide, zlrconia, stabilized z$rconia silicate~ magnesia, chrome-magnesite ~nd various combinatlons or ~ixtures of ~uch materi~ls.

1 Although other materlals are comprehended by the present lnvention, the lnsert 50 forming part of the n~zzle of the cruclble ls preferably construc~ed of boron nitride, silicon nitride, 5ilicon carbide, boron carblde, zirconia or quartz.

It is Imperative that the orlice passage of the noz21e lOa or lla remain open and ~ts configuration remain substantially stable throughout a strip castin~
operation. It ls understandable ~hat the nozzles should lC not erode or clog, signlficantly, durlng a multiplex strip casting sequence or certain objectives such as maintaining uniformity in the casting operation and of mlnimlzing metal flow turbulence ln the crucibles may be defeated Along these lines, lt appears that certain insulating ~aterials may not be able to maintaln their dimensional stabillty over long casting periods. To obviate this problem the nozzle lOa or lla, especially that portion defined by an lnsert 50, may be constructed of a material ~ which ls better able to maintain dimensional stabillty and integrity during exposure to high molten metal temperatures for prolonged time periods.

The drive ~ystem and housing for the drum~ wheel or other casting surface 16 of the present lnvention should he rigidly constructed to permit drum rotation wlthout structural instab~llty which could cause the drum to slip or vlbrateO In partlcul~r, care should be taken to ~void resonant frequences ~t the operating 6peeds for the drum.

The casting surface 18 ~hould be capable of moving at a surf3ce speed of ~rom about 200 linear surface feet per 1 minute to more that about lO,000 linear surface feet per minute. When utllizing a ~rum having a circumference of about B ~eet, this rate calcula~es to a drum speed from ~bout 25 rmp to ~bout 1250 rpmO A three horsepswer varlable ~peed reversible, dynamically bYaked motor provides an adequate drive system for an integral ~opper casting drum 2 to 10 ~nches thiek and about 8 feet ~n circumference.
Power requirements may have to be modified depending upon the type and size of casting surface 18 employed.
It should be appreciated that the casting surface 18 can be moved in a direction opposlte to that illustrated ln the drawin~, ~nd that the crucible may be disposed at any location about a circular casting wheel.

In one embodiment~ the c~sting surface 18 on the wheel or drum of the apparatus of the present invention ls smooth. It has been found that in certaln applIcations, such as for producing amorphous strlp portions, flnishing the peripheral surface 18 of a c~sting wheel 13 wlth 400-grit paper ~nd preferably with S00-grit paper may yleld improved product uniformity.

In an exempl~ry operation of the apparatus of the present inv~ntion, such as lllustrated in Figures 1 or 3, molten metal is delivexed to a first, heated crucible 10 and into a ~econd crucible 11, although such metal delivery may 2~ be sequenti~l rather than simult~neous. It is understood that ~ heater, such ~s ~nduction coil~ of reslstance wire 12, may be provlded ln and above the eruclbles 10 ~nd 11 to obtain or to maintain relatively constant molten ~etal ~emperature~ ~s ~ay ~e deslr2dO In ~he operatlon of the 1 apparatus of this lnvention metal may be poured directly into preheated crucibles. Such metal preheat temperature and the heatlng of the crucibles by ~uxlliary devices should prevent freezing or cloggfng of the nozzle durlng the lnitial castlng operation, ~nd the temperature of the flowing metal should thereafter keep the each crucible at sufficient temperature to insure unlnterrupted molten metal flow through each nozzle. In certain applications, the nozzle should be externally heated throughout the casting operation. Also, the metal which i5 fed to the crucibles may be superheated to allow a certain degree of temperatùre loss withoùt adversely affecting metal flow.

In Dne embodiment a metallostatic head height in the crucibles should be maintalned at a relatively constant level throughout the casting operation to assure that a ~elatively constant static head pressure may be maintained at the nozzle. This ~ay be accomplished by lnitially pouring the molten metal into each crucible to the desired height and thereafter controlling the rate at whlch additional molten metal is poured into that crucible to ~aintain the ~etallostatic head. It is understandable that the rate at which additlonal molten metal ls fed to the crucible should be ~n substantial ~onformity with the rate at which metal flows from the nozzle onto the casting surface 18 in forming ~5 the multlplex strlp material o~ the present invention.
Maintenance of a relatively constant height of me~al in the cruclbles assures that the molten metal flow pressure through the respective nozzle ls maintained relatively constant so ~ not to ~dversely 3ffect the c~sting oper~tion J.~

1 or the guality of the strip ~aterial. ~l~ernatively, as mentloned above, externally ~pplied pressure may be employed to control the pressure at the nozzles~

In the presen~ invention, a rapidly quenched S ~etallic strip 30 is cast onto the casting surf~ce 180 Such strip material 30 comprises a plurality of dissimilar portions, such as portions at b, c and d in Figure 5 or portions al, b, and a2 in Figure 6. Each individual portion of ~he strip 30 is metalluryically alloy-bonded to the edges of adjacent portlons along the longitudinal extent of the strip. ~urther, ~uch metallurgical alloy-bonding occurs as an lntegral part of the strp casting operatlon.

Strlp 30 having a plur~llty of dissimilar portions ls called ~multiplex strip~ or ~composite strip~ in this application. The multiplex strip 30 of the present invention is lntended to comprehend a strip having at least two dissimilar materials ~etallurgically alloy-bonded together along the longitudinal extent of the strip. This metallurgical alloy-bond occurs during the casting operation which forms the strip. The Wat least two different materlals~ preferably refers to different compositlons, however, such expression should also comprehend a multlplex strip which has the same composition but other properties which are different, lncluding, but not llmlted ~o~ electrical reslstivity, permeability, conductivlty, core loss character~6tics, yleld strength, h~rdness, ~tomic arrangement, gage, corEosion res$stance, thermal expansion, color and the like.

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~or purposes of illustrat~on, one portion of a multiplex strip of ehe present lnvention may have expansion - characteristics different from that of a bonded, adjacent portion. Thus, by heating or cooling such strip, an intentional curvilinear strlp material may be obtained. Also, the present invention may be employed to produce mult~plex strip having amorphous strlp portions metallurgically alloy~bonded to crystalline s~rip portions. ~hen a strip of ~morphous ma~erlal is joined by conven~ional means, involving heating, such as welding, to a strip of crystalline material the a~orphous strip becomes very brittle since the t~mperature to which lt is exposed exceeds the crystallization temperature.
By the present lnvention, however, the quench rate is so r~pid that crystalllzation of the amorphous strip portlon is substantially avoided, except posslbly at the transition zone.
The rapid quenching of a strip casting operation may also be beneficial in the production of certain crystalline ~trlp materials. Fast quenched crystalllne alloys, ln general, typically develop a highly deslrable microstructure which is finer than conventionally produced crystalline materials, Also, rapidly cast crystalline materials may contain desirable ~lloy phases not found ln conventional crystalline materlalsr and, conversely, rap~d casting may ~void or lnh~blt the formatlon of adverse alloy phases.
Additlonally, rapld casting can produce new alloy phases in crystalline materlals which although are metastable, typically exhlbit lmproved propertiesO

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1 In one preferred embodiment, the present lnvention pertalns to the manufacturing of multiplex strip 30 having an amorphous alloy portlon wh~ch ls formed with an adjacent ~etal or metal alloy portlon, which may or may not be amorphous, the latter porton being integr~l with the first mPntioned amorphous alloy portion. In the present invention the ~ultlple strlp portions may be cast simul~aneously adjacent one another onto the casting surface 18, as shown in ~he embodiment lllustrated in Figures 1 and 2. In thls embodiment, the multiple nozzles lOa and lla each deposit a stream of molten metal 20 ~nd 22, respectively, onto approximately the same transverse line across the casting surface 1~, adjacent to one another.~ As best shown ln Figure 2 the mol~en st~ea~s of metal converge to join one another and an actual alloying of the two converging streams actually occurs at the interface, also called the transltion zone. It wlll be appreciated tha~
the quench rate ls so rapid in the casting of metallic strip material, that the merging stream~ do not experience suffl~ient resldence tlme to significantly adversely affect the integrity of either metallic stream outside of the transition zone.
Therefore, the composition, gage~ hardness, strength, ductility, corrosion resistance and other propertles of one port~on of the strip ars not adversely affec~ed by the contact between adjacent portlons even in thelr molten ~t~te.

Alternatlvely, the multiple strlp por~ion may be cast successlvely onto the c~sting surface 18 as shown ln the embodiments lllustrated in Figures 3 and 4. In such embodiment, a ~tream of molten metal ls ~ed from one crucible -7~

1 10 onto the castlng surface 18. A second crucible 11 ls located downstream of the first crucible 10 with respect to the casting dlrection illustr~ted by the Drrow ln Figure 3.
The second crucible 11 has a nozzle lla whlch ~ust be disposed uch that ~ perlpheral edge portion of the second ~tream of metal contacts a peripheral edge portlon of the first metal to create a metallurgical alloy-bond therebetween during casting. It will be appreciated ~hat the first stream may be molten, partially solidified or even ~otally 601idified when the second stream contacts the peripheral edge. Wh~t is required by the casting operation is that a metallurgical alloy~bond be created therebetween as the multiplex strlp is formed~

Although the development has been discussed with relation to two streams of metal to produce a duplex strip, it should be understood that any number of dissimilar portions may be metallurgically alloy-bonded together in the present lnvention. For example, Figure 5 lllustrates a ~. multlplex strip composed of four portlons a, b, c and d cast from four separate crucibles A, B, C and D. Also, Figure 6 ~llustrates a trlplex strip which may be cast by disposing two streams of metal from two separate nozzles ln a common cruclble A adjacent both edge portions of a single strip portlon, b; from tundish B to produce ~ multiplex strip 2S having portlons al, b ~nd a2 metallurgically alloy-bonded during c~stlng. It will be ~ppreclated that ln ~hl~ embodiment the two nozzles of cruclble A are preferably sep~rated by a brldge of ~pproximately the same wldth a~ the central strlp portlon b.

-4;2~

1 In forming the metallurgical alloy-bond between ~djacent dissimilar portions, such dissimilar ~trip portions are fu6ed to one another. The joint be~ween ~djacent d~s~lmilar portions, which is called ~he ~transition zone"
throughout this application, extends throuqh the strip from its upper face to its lower face in a direction ~ubstanti~lly parallel to the longitudinal axis of the ~trip. Although the transition zone is illu~trated in chain lines in the drawings, it should be understood that ~uch transition zone may not be readily discernable by ordinary observation.

One preferred embodiment of this invention may he directed to the production of razor blade 6tock. In ~uch embodiment the composition of the metal in the flr~t crucible 10 is preferably chosen to produce an amorphous alloy having properties of strength, hardness, ductility and corrosion resistance which properties are generally desireable for forming a razor blade cutting edge portion. The composi~ion of the metal in the second crucible 11 may be chosen to provide a eultable backing material for the cutting edge portion of the strip.

Example A two-piece, or duplex~ metal alloy strlp was formed in accordance wi~h the present lnvention using two crucibles, ~imilar to that lllustrated in Figure 3. The ca~tlng surface comprlsed a 3.8 cm perlpheral surface of a 20 cm diameter copper wheel rotated at a 6peed of 32 meters per second wlth the axis of rotation being ~ubstantlally horizontal. In this example the crucible located slightly 7~

1 downstream w~th respect to the other crucible shall be referred to as the ~first cruclble~. The first ~rucible 11 was made of ~ilica and had a generally circular cross-sectlon with ~n internal diameter o~ 10 mm tapering to a slit nozzle with internal dimensien~ of 5 mm by 0.42 m~0 The botto~
~urface of the nozzle was maintained at about 0.43 mm above the casting ~urface, and the nozzle was disposed substantially parallel to the axis of the wheel. The first crucible 10 contained about 8.4 grams o ~n alloy co~position Fe83 Sis B12, based on an ato~ic percent. This alloy is hereinafter called Alloy I.

The second crucible 10, also made of silic3, was of circular cross-~ection with an internal diameter of l0 ~m, taperlng through 24 mm to a circular orifice having an internal diameter of about 0.64 ~ The bottom surface of the nozzle was maintained at about 0.43 mm ~bove the casting surface. The second crucible 10 was displaced about 5mm from the first cruclble ln a direction opposi~e to the rotat~on of the wheel. The second crucible 10, con~ained about 5.6 gra~s of an alloy composition Fe40 Ni40 B20~
based on atomIc percent. The alloy ls hereinafter called Alloy II, One edge of the nozzle orifice of the second ~rucible 10 was disposed sn the same circu~feren~ial line wlth respect to the wheel as one edge of the nozzle orifice of the first crucible, 80 that the two nozzle oriflces would not, i tr~nsposed, subst3ntlally overl3p.

In this example, both cruclble~ 1~ and 11 lay ln the g~ner~l pl~ne described by the wheel~ A~ me~sured in 7~

1 a direction opposite to that of the rotation of the wheel, the firEt crucible 11 being 1.5 $rom the vertical and the 6econd cruclble 12 being 40~ from the vertical. In this e~ample, the cruclbles were heated to about 1350C with an induction heating coil 60 as to melt thelr contents. ~he atmo6phere ln the crucibles was argon at atmospheric pressure, although protective atmospheres are not essential in this invention. The casting surface was moved past ~he nozzles at a peripheral ~peed of 32 linear meters per ~econd and the crucibles were simultaneously over-pressured with argon to expel their contents, the first crucible 11 at 2 psi and the second crucible 10 at 7 p~i. A continuous duplex strip was formed which was ejected from the ca~ting surface in abo~t one half of one second.

The strip was flat, having a width of about 4.5 mm.
The strip portion originating from the first crucible 11 was about 2.7 mm wide and about 30 microns thick with the remaining portion approximately 50 microns thick. The rlbbon was ductile and when caused to fail under test, showed no preferential parting at the joint, or transition zone. ~oth portions of the strip in this example were ~morphous.

I~ has been found that beyond a very small distance from the ~oint between the two part6 of the ribbon, on the order o~ le~s than 0~5 mm, the composition of one portion is not contaminated by ~etals from the other. Thus, ~nalysing ~or nickel on the ~7heel f~ce of the strip, a bold nickel peak ~7as ob~erved for 1.~ mm dropping to zero peak height over a distance of 0.05 mm 3t the junction. See ~he nickel -2~-7~

trace illustrated in Figure B wherein the height of the nickel trace is directly proportional to the amo~nt of nickel ln the Alloy II portion of the strip~ Also~ a scan for ~llicon had a ~harp cutoff at the junction thereafter dropping to æero peak hei~ht. See the s~liGon trace 111u6trated in Figure 9 wherein the height of the silicon trace is directly proportional to the amount of silicon in the Alloy I portion of the strip. The horizontal axis of the graphs of Figures 8 and 9 conno~es distance, with the eraced portion extending over a full distance of approximately four millimeters.

The graph ilu6trated in Figure 10 6hows the ~noop hardness of this strip at a load of 200 gram~. This graph illu~trates that the transition zone, i.e. the extent of the joint where Alloy I and Alloy II strip portions are metallurgically alloy-bonded together~ has a width of about 1 15 mm. As shown in Figure 10, the strength of Alloy I and Alloy II, respectively, remain~ substantially uniform outside the transition zone. It i8 noted that although the strength of the strip at the transition zone ~sually has ~ value between the strengths of adjacent portions, with certain alloys, the ~etallurgical alloy-bond at the transition zone may exhibit a strength which i5 higher or lower than that of the adjacent portions, or the transition zone may consist of a separate ~lloy exhibiting ~ther desirable propertie~ including corrosive resistance, electrical resistivity~ ~nd the like. Thus, by appropriately choosing the diss~milar alloys, a comblnation alloy can be formed wlthin the tran6ition zone. Likewlse!
appropriate ~lloys may be chosen whlch could prod~ce crystalline -26~

1 strIp portlons ~nd an amorphous transition zone, or vice versa.

In general, the transitlon zone metallurgically alloy bonding dissimllar ~trlp portions has an ldentiflable wid~h of less than about 1.50 mm or less than about fivP times the average gage of the bonded di~similar portions. ~ore preferably, the width of the transition zone is less than three t~mes the average gage or thlckness of the bonded portions.

While partIcular reference has been made to a duplex strip, lt ls also possible to produce multiplex strips having ~ny number of dissimilar portions, by ~he present invention. For example, a multiplex strip can be produced which has a composltion preferred for a cutting edge of a razor blade on both marg~ns and an lntermediate broad band of material appropriate for backing the cutting edge material. Such strip may then be ;formed int~ double edge razor blades or may be split longl~udinally to provide single edge blades. In another examplè, the cut~ing edge composition of stainless steel may be used for a central portlon of the strlp, which ls subseguently ~plit longltudinally through the central portion to provide two strips of duplex form. A posslble ~dvantage of such triplex strlp ls the malntenance of lts form when coiled for purposes of storage Dnd ~ubsequent processing.

Durlng the colltlnuous castlng of multlplex strip materlal, the tendency of the strip 30 ~o adhere to the ~astlng ~ur~ce 18 or ~ signlflc~nt dlstance, such as I

1 ~everal feet or more, beyond the nozzle has been observed.
This phenomenon is beneficial ~n ca~ting multiplex ~trip through staggered nozzles, such as ~hown in Figure 3, 5 and 6 however, it i6 understandable that if the ~tr~p ~aterial remains on a rotating ca6tlng drum or wheel 13 f9r a full revolutionl damage to the cruclbles could re~ul~. It has been found that the u~e of a doctor blade, such as a knife type element riding at or near the drum ~urface 18, approximately 2~5 to 6 feet from the nozzle may counter 6uch adherence. With such an arrangement, the cast strip may be removed from the drum by ~uch doctor blade. Such doctor blade has been found part~cularly useful in the production of thinner amorphous strip materials which appear to have a greater tendency to ~dhere to the casting ~urface 18 than do the crystalline strip materials. It is believed that the force whlch retains the strip on the casting surface reflects the q~ality of the thermal contact between the strip and the casting surface. Alternative arrangements, such as an air knife, may al80 be employed to separate the atrip from the wheel.

The casting of relatlvely high quality multiplex strip material, po6sibly including ~morphous strip portions, which for the purpose of th~s invention includes materials which are at least 50~ amorphous, is feasible and practical using the apparatu6 and procedure6 described aboveO
Understandably, the quench ~ates must u6ually be higher for ~morphous materlal as compared to ~rystall~ne material.
When nece~sary quench rates may be accelera~ed such as by inc~ea~ing the cpeed v the ~a6ting 6urface~ or the l~ke.

L2~

1 Typical alloys which may be cast into Multiplex strip ln accordanc with the present invention include those ~n whlch at least one portion comprlses an alloy h~v~ng iron, nlckel, cobalt and combinations or mlxtures thereof as a major constituent. Major constituents ~re thoss which dominate the composit~on such ~hat no other element ls presen~ ln a larger amount, based on atomic percentages. Such alloys typically contain, as minor constituentst siliconr boron, phosphorus, carbon, alumlnum, vanadium, berylllum, chromium and combinations or mixtures thereof. Only incidental lmpuritles, less than one percent, and preferrably less than OD1%~ should be present in such alloys. ~s mentioned above, such alloys are preferably amorphous, however crystalline alloys and combinations of crystalline and amorphous alloy portlons are comprehended by the multiplex strip of the present invention. Preferred iron-base alloys for portions of the strip of thls invention include the following:

Fego_8s Si3~7 ~10-15 Fe36-43 Ni36-43 Bl7-22 Fego B12 Si8 Fe7g B15 Si6 Fegl Rl~ Cl F~4 B15 Sil Where~s the preferred embodiment has been 25 descrlbed above for the purposes of lllustr~tion, lt will be ~pparent to those ~kllled ln the art that numerous variations of the det~ils may be m~de without departlng from the ~nvent ionO

Wh~t ~6 claimed ~:

Claims (22)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A rapidly quenched, thin cast metallic strip having an upper face and a lower face; said strip comprising a plurality of rapidly quenched, cast metallic dissimilar portions of at least two different compositions cast edge-to-edge, each portion having contacted a casting surface and metal-lurgically alloy-bonded during casting to an adjacent portions along the edges of said dissimilar portions of said strip;
said strip having the metallurgical bond formed at a transition zone between portions having a width of less than five times the average thickness of the bonded portions and extending through the strip thickness from one face to the other face of the strip.

2. A strip as set forth in claim 1 wherein at least two adjacent portions of said strip have dissimilar atomic arrangement.

3. A strip as set forth in claim 2 wherein at least one dissimilar portion of said strip is amorphous.

4. A strip as set forth in claim 2 wherein at least one dissimilar portion of said strip is crystalline.

5. A strip as set forth in claim 1 wherein the metal-lurgical alloy-bond is formed at a transition zone which is amorphous and wherein the dissimilar portions adjacent said transition zone are crystalline.

6. A strip as set forth in claim 1 wherein adjacent dissimilar portions are amorphous and the metallurgical alloy-bond is formed at a transition zone therebetween which is crystalline.

7. A strip as set forth in claim 1 wherein at least one dissimilar portion of said strip is stainless steel.

8. A strip as set forth in claim 1 wherein at least two adjacent portions of said strip have dissimilar thicknesses.

9. A strip as set forth in claim 1 wherein at least two adjacent portions of said strip have dissimilar corrosion resistant properties.

10. A strip as set forth in claim 1 wherein at least two adjacent portions of said strip have dissimilar electrical properties.

11. A strip as set forth in claim 1 wherein at least two adjacent portions of said strip have dissimilar expansion characteristics.

12. A strip as set forth in claim 1 wherein at least one portion comprises an alloy having major constituents selected from the group consisting of iron, nickel and cobalt and mixtures thereof and minor constituents selected from the group consisting of silicon, boron, phosphorous, carbon, aluminum, vanadium, beryllium, chromium and mixtures thereof, with incidental impurities.

13. A strip as set forth in claim 1 wherein at least one portion is at least 50% amorphous and has a composition of Fe80-85 Si3-7 B10-15, based on atomic percentages.

14. A strip as set forth in claim 1 wherein at least one portion is at least 50% amorphous and has a composition of Fe36-43 Ni36-43 B17-22, based on atomic percentages.

15. A strip as set forth in claim 1 wherein at least one portion is at least 50% amorphous and has a composition of Fe80 B12 Si8, based on atomic percentages.

16. A strip as set forth in claim 1 wherein at least one portion is at least 50% amorphous and has a composition of Fe79B15 Si6, based on atomic percentages.

17. A strip as set forth in claim 1 wherein at least one portion is at least 50% amorphous and has a composition of Fe81B13Si5C1, based on atomic percentages.

18. A strip as set forth in claim 1 wherein at least one portion is at least 50% amorphous and has a composition of Fe84B15Si1, based on atomic percentages.

19. A strip as set forth in claim 1 wherein the metal-lurgical bond is formed at a transition zone between portions having a width of less than about 1.5 mm.

20. A strip as set forth in claim 1 wherein the metal-lurgical bond is formed at a transition zone having mechanical strength greater than that of both adjacent bonded portions.

21. A strip as set forth in claim 1 wherein the metal-lurgical alloy-bond is formed at a transition zone having lower mechanical strength than that of both adjacent bonded portions.

22. A method of casting metallic strip having a plurality of dissimilar portions metallurgically alloy-bonded along the longitudinal extent of said strip comprising the steps of:
delivering a first stream of molten metal from a nozzle of a first crucible onto a casting surface moving at a rate of from 200 to 10,000 linear surface feet per minute past said nozzle, and delivering at least one additional dissimilar stream of molten metal from a nozzle of a second crucible onto said casting surface such that a peripheral edge portion of said at least one additional stream contacts a peripheral edge portion of adjacent dissimilar metal to creat a metallurgical alloy-bond therebetween during casting.